1. Field of the Invention
The present invention relates to an ultra clean stainless steel for use in the manufacture of extremely fine wire, and its production, with inclusions in the steel being reduced to the highest degree.
The ultra clean stainless steel of the present invention is ideal for stainless steel wire used in such products as fine wire mesh, precision filters, or printing mesh for IC printed circuits or glass products.
The stainless steels to which the present invention can be applied are Cr-based and Ni-Cr-based stainless steels. These stainless steels may further contain suitable special elements for the purpose of improving their properties.
2. State of the Art
For the uses mentioned above, a stainless steel extremely fine wire with a diameter of 30 micron or less is required. At present, the finest wire that can be manufactured from industrially produced stainless steel has a diameter of 40 micron, and the above requirement can not be met. Using existing materials, breakage occurs easily at the time of wire drawing and drawing yield is noticeably decreased.
In the manufacture of extremely fine steel wire, the cleanest possible material must be prepared. The material for the above-mentioned 40 micron extremely fine wire is produced by AOD (argon oxygen decarburization) slag refining followed by electroslag remelting (hereafter referred to as ESR) which is considered, until now, to be one of the cleanest steels available.